There are many applications where it is desired to tighten a nut to a given torque which will retain the torqued condition, without requiring the use of separate means such as cotter pins, or distortion of parts of the assembled joints.
A well-known application is in place of the conventional wheel bearing nut, in which one race of a wheel bearing is held to a spindle by a nut tightened to a predetermined torque. When the nut is appropriately tightened, it is backed off so one of its castellations is aligned with a cotter pin passage. A cotter pin is then passed through and its ends sent to hold the nut in a position which makes a near approximation to a desired torqued setting. Thereafter to remove the nut, the cotter pin is cut. Replacement involves a repetition of the first procedure.
The disadvantages of this arrangement have not gone unnoticed, and wheel bearing nuts have been devised which are self-locking in the sense, that the locking feature can be disabled by an installation tool while the nut is being tightened or released. Well-known examples are shown in Greenwood U.S. Pat. No. 3,581,609 and Wing et al U.S. Pat. No. 3,851,690. It is an object of this invention to improve on wheel bearing nuts of this general class.
Such nuts require the exertion of an axial force on some part of the nut assembly while exerting a tightening torque. This feature is utilized in the instant invention, also.
An examination of prior lock nuts of this class reveals that, even though some have been very successful, they require more parts than one would wish to use. Nuts of this type are used in the millions each year, and the elimination of a part can constitute a remarkable cost saving. The construction of this invention requires only three parts, all of which can be made with classic inexpensive procedures. For example, the more complicated parts can be made with powdered metal technology, thereby drastically reducing the cost of the nut.
Accordingly, it is an object of this invention to provide a self-locking lock nut which utilizes only the absolutely minimum number of parts (three), whose parts are very economical to manufacture and assemble, which is convenient to install and remove, and which is highly reliable as it must be for a part as critical as a wheel bearing nut.